1. Field of the Invention
The present invention relates to a liquid jet recording head that forms liquid droplets by discharging liquid, such as recording liquid, from discharge ports (orifices), and also, the invention relates to a recording apparatus provided with such a liquid jet recording head.
In this respect, even among ink generally considered dyestuffs ink, there are inks that eventually precipitate colorant. For the present invention, it is to be understood that ink that eventually precipitates colorant, including dyestuffs ink of the kind, is called collectively pigment ink.
2. Related Background Art
A recording apparatus that mounts a liquid jet recording head can be cited as a typical recording apparatus that adopts a liquid jet recording method, a method which makes it possible to perform high-speed recording and to record on various kinds of recording media.
For the liquid jet recording head of the kind, the method of discharge that uses an electrothermal converting element is known as the typical discharge method, in which liquid droplets are discharged from fine discharge ports for recording on a recording medium. The liquid jet recording head generally comprises a liquid jet recording head that records on a recording medium by discharging recording liquid from discharge ports, and a recording liquid storing chamber that contains recording liquid to be supplied to the liquid jet recording head.
Now, as the recording liquid, which is discharged from the aforesaid liquid jet recording head, there is primarily dyestuffs ink and pigment ink.
Unlike dyestuffs ink, in which the colorant is dissolved, pigment ink has large colorant grains, and it has the advantage that discoloration does not occur easily, because it is excellent in light resistance when exposed to light after recording. On the other hand, the colorant in the ink settles more easily, and if the pigment settles and is separated, there is a fear that the densities of the object recorded by the liquid jet recording head are significantly degraded, and/or that clogging takes place in the discharge ports (orifices) of the liquid jet recording head.
Therefore, if pigment ink is stored in the liquid jet recording apparatus for a long time, there is a fear that the porous member, such as a filter, provided for the liquid supply passage for the purpose of removing impurities or dust particles in the recording liquid, may become clogged, or that the liquid supply passage itself may become clogged. Once a problem such as this occurs, ink is no longer able to reach the discharge port portion at the downstream end of the apparatus, thus preventing ink discharge from the discharge ports of the liquid jet recording head.